Let's roll up our sleeves and solve this. We have 125 and we're going to multiply it by 36, essentially adding 125 to itself 36 times.
Step 1: 0 + 125 = 125
Step 2: 125 + 125 = 250
Step 3: 250 + 125 = 375
Step 4: 375 + 125 = 500
Step 5: 500 + 125 = 625
Step 6: 625 + 125 = 750
Step 7: 750 + 125 = 875
Step 8: 875 + 125 = 1000
Step 9: 1000 + 125 = 1125
Step 10: 1125 + 125 = 1250
Step 11: 1250 + 125 = 1375
Step 12: 1375 + 125 = 1500
Step 13: 1500 + 125 = 1625
Step 14: 1625 + 125 = 1750
Step 15: 1750 + 125 = 1875
Step 16: 1875 + 125 = 2000
Step 17: 2000 + 125 = 2125
Step 18: 2125 + 125 = 2250
Step 19: 2250 + 125 = 2375
Step 20: 2375 + 125 = 2500
Step 21: 2500 + 125 = 2625
Step 22: 2625 + 125 = 2750
Step 23: 2750 + 125 = 2875
Step 24: 2875 + 125 = 3000
Step 25: 3000 + 125 = 3125
Step 26: 3125 + 125 = 3250
Step 27: 3250 + 125 = 3375
Step 28: 3375 + 125 = 3500
Step 29: 3500 + 125 = 3625
Step 30: 3625 + 125 = 3750
Step 31: 3750 + 125 = 3875
Step 32: 3875 + 125 = 4000
Step 33: 4000 + 125 = 4125
Step 34: 4125 + 125 = 4250
Step 35: 4250 + 125 = 4375
Step 36: 4375 + 125 = 4500

So, 125*36 = 4500